1. Department of Oncology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197 Ruijin er Road, Shanghai, 200025, China.
2. Shanghai Institute of Digestive Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, No. 197 Ruijin er Road, Shanghai, 200025, China.
# These authors contributed equally to this manuscript and should be considered co-first authors
Purpose: The present study focused on the long-term prognostic value of dynamic body mass index (BMI) change in gastric cancer patients who underwent gastrectomy.
Methods: Clinical data from a total of 576 gastric cancer patients who underwent radical gastrectomy were collected. Univariate and multivariate analyses were performed to demonstrate the association between dynamic BMI variables (BMI before surgery, 1 month, 6 months or 12 months after surgery) and prognosis (DFS and OS). The correlation between BMI loss after surgery and survival outcomes was also evaluated.
Results: Post-operative BMI, especially BMI at one year after surgery (p<0.001), was an independent risk factor of recurrence and mortality, wherein patients with high-BMI (≥23) showed significantly better outcomes than patients with normal-BMI (18.5-23) (DFS, HR:0.49; 95% CI:0.31-0.78; OS, HR:0.30; 95% CI: 0.15-0.59). On the contrary, low-BMI (<18.5) patients presented with worse outcomes (DFS, HR: 1.34; 95% CI: 1.00-1.80; OS, HR: 1.68; 95% CI: 1.20-2.34). In addition, compared with moderate BMI loss (≤10%), severe postoperative BMI loss (>10%) at one year was independently associated with substantially worse prognosis for DFS (HR: 1.54; 95% CI: 1.15-2.08) and OS (HR: 1.45; 95% CI: 1.02-2.06). Subgroup analysis indicated that gender (p=0.03), extent of resection (p<0.001), tumor site (p=0.001) and perineural invasion (p=0.007) were associated with postoperative BMI loss at one year. The prognostic value of postoperative BMI loss at one year was consistent among most clinicopathological subgroups, except for tumor site (interaction p=0.025 for OS).
Conclusion: In Chinese gastric cancer patients who underwent gastrectomy, higher postoperative BMI (≥ 23) was significantly associated with longer survival time, whereas severe BMI loss (>10%) at one year after surgery was associated with worse outcomes. Thus, body weight maintenance after treatment is important, and dynamic monitoring of body weight and nutritional status should be emphasized in clinical practice.
Keywords: gastric cancer, body mass index, weight loss, prognosis